Abrasive cement



' No ilirawing.

Patented Nov. 1927.

UNITED STATES PATENT OFFICE.

HERBERT 0. BAY, OF GMNDMEBE, QUEBEC, CANADA, ASSIGNOB T LAUREI NTIDE COMPANY LIMITED, OE GBANDMEBE, QUEBEC, "CANADA.

ABBASIVE CEMENT.

This invention relates to the production of a suitable cementing material for binding or cementing sandstones together, in order 'to form a grinding stone of suitable diameter and face width.

Inobtaining pulp grinding stones from sandstone quarries, considerable difliculty is experienced in obtaining suflicient masses of clear sandstone material, free from defects, out finished stones suit-' to pro uce pulp grinding stones, and the like, of suitable face width, from smaller stones cemented together and in which the cementing material will not crumble away in service, thus. leaving a crack or opening in the face of the stone. A further object is to produce a -c menting material forcementing surfaces ofstones, which material will contain an'abrasive aggregate adapted to perform its work in grinding as evenly as the sandstone itself, and which cementing material will be insoluble in. hot water, will be strongly adhesive, will be sufficiently hard to re-inforce the edges of the stone so that the dressing burr will not crush of! the edges, and also which will be sufliciently porous to prevent glazing at the grindin gsurface.

I have found that the above important properties may be obtained 'by using resin dissolved 'in an organic solvent asa binder for an abrasive aggregate. The resin which i I find most suitable is a phenolic formaldehyde. resin preferably such as set forth in British Patent No. 9,291: of 1914 to Laurence Vincent Redman. Resins of this character are formed by incorporating hexamethylenetetramine with a phenol and heating the mixture, the excess of either reagent being removed or left in the compound as desired.- Resins of this character may be manufactured by mixing the ingredients in suitable proportions to form a product which can be converted into an insoluble iii/fusible chemically inert substance. The preferred proportion is one. and one-half phenol groups denatured alcohol.

by a slighhreciprocating' motion of one part Application and Augult 11, ,1925. Serial n. 40,049.

to one methylene group although it is obvious that this proportion may be somewhat varied. The best results have been obtained by using Resin No. 201 known under the name of Redmanol and manufactured by the Bakelite Corporation. However any 5 similar artificial resin, capable of solution by an organic olvent, may be employed. Inthis connection, it may be noted thathexamethylenetetramine is the equivalent of formaldehyde. This abrasive cement consists of the following ingredients and is made up in the following manner; about 90 parts, b weight, of cleanv dry fine sand which will pass through a 28 mesh sieve and be retained an a 100 mesh sieve, are thoroughly mixed'yfi" dry, with 10 parts, by weight, 0 a' phenolic formaldehyde resin, and to this mixture --isadded parts, by weight, of furfural mixed with 2 parts, by weight, of an alcohol such as ethyl alcohol, the whole mass bebig throughly mixed and kneaded together until all of'the grains of sand are completely wetted by'the dissolved resin.

Before applying this abrasive cement to the surfaces to be cemented I find it prefers able to apply to said surfaces a preliminary coating consisting of approximately 10 parts, by weight, .of a phenolic formalde-. hyde' resin and 3 ,4; parts, by weight, of furfural mixed with 2 parts, by weight, of The prepared surfaces may then be coated with about of an inch of the abrasivecement and when the cement between the 'parts is. consolidated,

on'theother, the parts are clamped together and put into an oven and heated, gradually,

to a maximum temperature of about 215 C. The time for bringing the temperature to maximum depends upon the size of the stones. For very large stones this period should extend for about four days. The cooling period should be slow and shouldoccupy about the same timeas the period of heating. 1

I have found.that stones cemented together with this abrasive mixture will have all the grinding qualities of solid sandstone.

I have found-that denatured grain alcohol furiural approximately 3 parts, and alcogives satisfactory results and it may be used hol approximately 2% parts, byweight, all 10 m lane of the ure alcohoL- thoroughly mixed and kneaded together into aving thus escribed my invention, what a cement paste. 5 I claim is In witness whereof, I have hereunto set An abrasive cement, consisting of fine my hand. sand approximately 90 parts, a henolic formaldehyde resin approximate y 10 parts, HERBERT O. KEAY'. 

